Cellulosic product



Jan. 18, 1944-. c; A. FOURNES$ ET AL 2,339,326

CELLULOS IO PRODUCT Filed Jun e l9, 1940. 2 Sheets-Sheet l 23 2 7 ir z/erzafmw zf z.

a (W Mm Jan. 18, 1944. c. A. FOURNESS ET AL. 2,339; 2 6

CELL-ULOSIC PRODUCT Filed June 19, 1940 2 Sheets-Sheet 2 "ablyand excessiv'elyhigh.

Patented Jan. 18, 1 944 cmunosrc mnuc'r y chal t A s-Formica: m John B. Catlin, Appleton,

Wia. arlignon to Patents Ncena.h;zwis.,'acclimation or-Wiaconsin 1 application June 19. i94c, sr a 1vt.s41.2s2 i 7 Claims. (cairn-54 creped, cellulosic products such as are disclosed iii-United States'Letters Patent No. 2,102,233'to Frank-A. Biederman and No. 2,170,655 to Charles A. Fourness, both of which, patents'are assigned;

to the assignee of this invention. This applicaprise a pad or bat of low unit density which is I 1 The present invention relates. to I multi-plY.

' an be restored many time to a low de slts high bulk condition so as to render it suitable foruse.

'tion is a continuation in part of our prior appliwjj cationSer. No. 114,590 which was filed December '1, 1936. and which is also assigned to the assignee r of this application. h Products of the type disclosed in the above mentioned Biederman and Fourness patents com-.

formed by superposing a. plurality of generally flat layers of thin, creped, cellulosic tissue. For certain uses, as disclosed and claimed in the Fourness patent the individual sheets contain asphalt or other thermo-plastic material in .varying amounts. Certain of the thermo-plasticbearing:

products are water resistant to a very'high de- 'gree. If desired, any of the productsmaybe also fireproofed.

Products of this type are widely used as packing materials, liquid absorbing, 0r filtering ma-" terials, and as; insulating materials, for both heat andfsound 'ihsulation, the asphalt bearing prod-1 not being particularly satisfactory for insulation,

uses. However, becauseof the extremely large bulk of. these products with .respect to their weight, the boxing, shipping, storingyand handling costs of the products have been unreason Heretofore, all attempts to shipment, storage, etc. have resulted in serious increase the unit" density of these products for the purposes of More particularly, we have discovered that any of the. multi-ply, high bulk, low density bathr pad products described in the above mentioned IBiederman and. Foumess patents can be con-Q 1 verted into a relatively dense,.low' bulk product by longitudinally compressingthe original bat or pad in a direction substantially perpendicular toj the creping therein, 'andthat'the resultant compressed product, contrary to the products produced by ordinary methods of compression, can j. be readily restored to its originalrlow density,

high bulk state at any. time merely by longitudinally extending the compressed pad or'bat, as by stretching. a

This intermediate compressed product .when

manufactured in accordance with the present in-.

vention is of suiliciently low bulk and of suflicient- 1y high unit .density to-permit economical and co'nvenient boxing, shippin8, handling, and stor-'" ing thereof, while at the same time the inter-' mediate product can conveniently and easily be. restored to its original state. or great bulk andlow unit density when it is desired 'to use the product.

Moreover. this intermediate compressed prod-juct is found to. possess certain very remarkable and quite unexpected properties not possessed by the original product. The bulk of the restored 4 product," for example, is even greaterv than the V bulk of the originalproduct, and when the prodnot is used as an insulating material this. in-

' crease correspondingly improves theinsulating Y I efliciency of the product as compared with *the- 1-- 'efliciency of the original product. Further, the

impairment of the properties ofthe products.

Attempts.to bale these products,'. for example.-

by. -any of the known baling methods accomplish the desired reduction in bulk and increase in unit density,- but the reduction of bulk for practical purposes becomes permanent, and the product cannot be restored by any commercially-practical procedures to its useful low density, high bulk condition after it has once been compressed and baled. In, fact, the deleterious effects of compressing the products even slightly are so serious that heretofore it has been necessary to ship and handle the product in rigid cartons or containers.

We have discovered, however, that contrary to the accepted teachings and practices of the' art, the subject low density, high bulk products described in the above mentioned Biederman and Fourness patents can be converted into intermediate products of relatively low bulk and of relatively high density, which intermediate products lengthJof the restored product can be readily controlled within rather wide vlimits. This means that a single standardized article may be used h for insulating spaces of relatively widely varying physical dimensions and makes possible anew and highly desirable method of insulating buildings, wall spaces, and the like. If the longitudinal compression and restoration of the product is repeated a number or times, it has been found that the bulk of the product may be increased as much as a hundred per cent, with corresponding increased improvement in the product as an insulating material since the insulating efliciency of products of this type issubstantially a function of the bulk of the product without regard to its density. l

Other advantages result from the use of the present invention in that the manufacture of the intermediate high density product may be contion of the article to its original state, as will be described in some detail in subsequent paragraphs. The invention also vfinds application for the purpose of increasing the bulk of the low density products of the'subject type.

These and other advantages of the invention and the preferred methods of accomplishing the same will be made more apparent by reference to the following description of certain preferred embodiments thereof and in the accompanying drawings, wherein- Figure 1 is a perspective view of a multi-ply pad or bat product of the type to which the present invention particularly pertains. A portion of the bat has been magnified to better illustrate the features thereof;

Figure 2 is an enlarged perspective view of a portion of one of the sheets making up the pad or bat product shown in Figure 1;

Figure 3 is a perspective view, similar to Figure 1, showing a multi-ply, relatively dense, cellulosic product-the intermediate product mentioned in the foregoing-manufactured in accordance with the present invention, this figure is drawn-to the same scale as Figurel;

Figure 4 is a perspective view, somewhat .dia-' grammatic in form, illustrating the features of an apparatus which may be used for producing the so-called intermediate product illustrated in Figure 3;

Figure 5 is a perspective view showing a bale of the individual units illustrated in Figure 3;

Figure 6 is a sectional ,view, somewhat diagrammatic in form, illustrating a press which may be i used for forming the bale illustrated in Figure 5;

Figure 7 is a fragmentary perspective view 11- lustrating one manner in which the product of the present invention may be utilized;

' Figure 8 is an enlarged view on the general line 88 of Figure '1; and

Figure 9 is a perspective view of a modified form of bale generally similar to that shown in Figure 5, this bale has been partially expanded.

As indicated in the foregoing, the present invention is primarily concerned with, although not necessarily limited to, products of certain specific types, namely the multi-ply, low density, pad or bat products disclosed and claimed in the above mentioned Biederman and Fourness patents. These products, as pointed out in the IBiederman. and Fourness patents, are manufactured by superposing a plurality of sheets of thin, creped, cellulosic tissue. The tissue sheets may be plaini (i. e. consist of from about 94 to 96% by weight of commercial cellulose fiber, ex-

clusive of clay or like inert filler material) or they may contain substantial amounts of asphalt (10 to 50% by weight) or equivalent thermoplastic material, as described particularly in the Fourness Patent 2,170,655. As manufacturedat the present time the pads or bats comprise about three to possibly 150 or vof the bats ranging from about one-eighth to two or three inches or more. The small magnified section of Fig. 1 illustrates the general-arrange- 5 ment of the sheets, and a portion of one of the individual sheets used in making the bats is illustrated in Fig. 2. The product, as manufactured, is very bulky, porous, and of low density, In addition to its desirable properties as a packing material, liquid absorbing material, etc., it possesses excellent thermal and sound insulating properties. I

If the sheets contain asphalt or other thermoplastic material, it is desirable that this material shall be in the form of small discrete particles of widely varying dimensions which are individually attached to the fibers or groups of fibers making up the sheet. Also it is practically essential that the thermoplastic material should be of a type whichis relatively brittle at room temperature and which has a melting point within the range of about 140 F. to 200 F. Asphalt or equivalent thermoplastic material of this type and in this form has the particular property of effecting marked reduction in the stable density of the product as pointed out in the Fourness patent.

Regardless of whether plain or asphalt containing sheets are used, the sheets have a basis weight, or more properly a dryer basis weight (i. e. weight of flat uncreped sheets), within the range of about 4 to 9 pounds for 480 sheets 24 x 36 inches. Both types of sheets are manufactured on a Yankee type machine and as manufactured I they have a crepe ratio (i. e. the ratio of the 35 length of the uncreped sheet to the length of the creped sheet) of about 2.0 to 3.0. The pad or bat product made from the asphalt containing sheets has a stable unit density (1. e. the density in which the product is self-supporting and may 40 be used) as manufactured within the range of about 1.25 to 2 pounds per cubic foot. The pad or bat product made from the plain sheets, and

superposed sheets extends in the same direction, {preferably transversely to the length of the bat.

As has been previously stated,'due to the extremely high bulk of these products the boxing, shipping, and handling costs have heretofore been excessively large andno means had been known whereby the density of products of this type could be temporarily increased. to permit economical handling, shipping, storing, and use of the product without permanently impairing the ability of the product to be reformed into a product possessing characteristics even approximating the desirable characteristics of the original product. It is with the overcoming of these difliculties and with the improvement of the characteristics of the original product that the present invention is particularly concerned.

All of the original attempts to decrease temporarily the bulk of products of this type have resulted in complete failure. If an attempt is made to bale the article by any of the known ordinary methods of baling, the product after it 70 .has'been baled seems to mat and becomes very difficult of restoration to anything even appreaching its original condition of large bulk and low density. However, we have discovered that if a pad or bat of the type illustrated in Figure 1,

15 and having physical properties as set forth in i. e. the creping in all,-or substantially all, of the.

the foregoing, is compressed longitudinally, i. e. in a direction generally perpendicular to the direction of the creping in the individual sheets making up th bat, a relatively high density product will be produced which can be easily and conveniently restored at any time to its original condition without loss or impairment of any of the uct is readily controllable by the user so that it will automatically accommodate itself to spaces of materially varying dimensions.

ber of sheets and originally, having the same dimensions as the product shown in Figure 1.

The product illustrated in Figure 3 is expansible from the compressed condition illustrated in that figure to a length substantially the same,'or possibly even slightly greater, than the product illustrated in Figure 1, i. e. is expansible back to its original length or greater.

The amount that the original bat is compressed may be varied through rather wide limits deone half is not advantageous, and a reduction in 40 length to one-twentieth of the original length is A compressed pad is illustrated in Figure 3, that figure portray- ,ing to scale an article comprising the same numinvention is shown more or less diagrammatically in Figure 4. This press includes suitable top, bottom and side members, I, 2, and 3, respectiveiv, for defining a rectangular chamber 4 of substantially the same dimensions as the bat which it is desired to compress. Necessarily these wall members must be capable of being swung open to permit the introduction of an uncompressed bat into the interior thereof. During operation of the press, a bat such as is indicated at- 5 in Figure 1 is placed within the chamber 4 and is compressed perpendicularly to the direction of the creping therein by means of a suitable plunger or ram 6 movable within the chamber 4. This plunger 6 may be actuated by any suitable means,

such as a hydraulic press or screw. The compressing of the bat 5 is accomplished merely by moving the plunger from the position illustrated in dotted lines in Figure 4 to the position illustrated in full lines in that figure, the resultant compressed bat, indicated at I, being identical with the bat shown in Figure 3.

In one commercial embodiment, the original bats are eight feet, four inches in length, fifteen 2 inches wide, and one inch thick, being made up of twenty-four separate plies or sheets of asphalt,

bearing, creped tissue. The original bats have a unitdensity of about 1.7 pounds percubic foot. The constituent sheets contain, on a weight basis,

about 83% cellulose, 12% asphalt, and 5% water,

.35 creping parallel to the fifteen inch direction.'

usually about as much as canbe conveniently accomplished by-the use of ordinary machinery.

In this connection, however, it must be noted that it is not possible to increase the density of the basis weights in excessof about 3.75 pounds. per

cubic foot.

The compressing operation is accompanied by certain physical changes in the product. The unit density increases in inverse ratio to the change in length of the original pad or bat, and the crepe ratio of the individual sheets is simi- 'larly increased. Thus for compressions which effect changes in length within the range of one- -half to one-twentieth, the compressed pad or bat product when made from plain or non-asphalt bearing sheets will have a unit density within the range of from about 6 to a maximum of about 75 pounds per cubic foot. When madefrom asphalt bearing sheets of the type described in Fourness Patent 2,170,655, the compressed prodnot will have a 'unit density within the range of case, however, the crepe ratio of the individual sheets making up the compressed product will be and they have a dryer or uncreped basis weight of 5.0 pounds for 480 sheets 24 x 36 inches anda crepe ratio as manufactured of 2.6. The superposed sheets are similarly arranged with the These bats may be readily compressed so as to reduce the eight ioot, four inch dimension to about twenty inches thereby increasing the unit weight of the product from about 1.7 pounds per cubic foot to somewhat in excess of 8.5 pounds per cubic foot (a compression ratio of about 5). The crepe ratio of the constituent sheets is increased from its initial value of 2.6 to 13.0. The compressed bat, as illustrated at I in Fig. 4, is preferably tied in position when the Plunger or ram 6 is in the full compressed position, or if desired, the bat I may be inserted directly into a suitable box or container inits compressed com I dition.

The resultant compressed product is of sufli-' cient density to permit its being shipped economically, and it is very convenient to handle,

ing either end of the article and pulling it out in a direction opposite to the previous compression thereof. Upon extension of the product to itsoriginal length, it will be found to possess even more bulk than the original uncompressed about 2.5 to 40 pounds per cubic foot.. In either increased as an incident to the compressing operation within the rangeof about 4 to 60.

A press suitable for accomplishing the manufacture oi the compressed product of the present bat, particularly if the compressing and extension operation is repeated several times. This increase in'bulk is sometimes as great as one original uncompressed pad thereby increasing the bulk of the expanded product. The thermal and sound insulating characteristics of the product are fully preserved and in all respects the (see Figures 7 and 8).

resultant article is as good, if not better, than it was prior to the compressing.

At this point it might be again stressed that it is'o'nly by compressing thearticle substantially perpendicular to the creping thereof and parallel to'the plane of the component sheets that this ability of restoration is accomplished. If the width and thickness of the original pad or bat are maintained substantially unchanged throughout the compressing operation, it will be found that when the compressed-article is stretched out its width is substantially the same as prior to the compressing operation.

A further desirable characteristic results during the use of the compressed article in that the amount of stretching during the restoration or expansion operation may be varied between fairly wide limits without any noticeable adverse effect on the desirable characteristics of the resultant product. This characteristic is very important in many instances as, for example, when the product is used as wall insulation for the spaces between the upright studs of the frame of a house In such installations the distance between the top and bottom studs varies in different buildingsand sometimes in the same building, the usual limits being from seven feet six inches to nine feet, and heretofore it has been necessary for the contractor or workman to cut insulating bats to the various different lengths encountered on any particular job. By the present invention one standardized product which is very easy to handle will fit practically all buildings, and our invention thus makes pos-' sible a new method of insulating buildings.

In installing the compressed product of the present invention in such locations in accordance with the new method of our invention, the upper end of one of the compressed bats l is first fastened in place, as by a lath 9, the lath 9 being tacked, through to the upper stud H, as is shown particularly in Figure 8. Then the lower end of the bat is grasped in both hands by the carpenter, or other workman, and is extended or stretched to a sufiicient length to fill the stud space. During the stretching operation the bat is fluffed a little by shaking to assure the attainment of the maximum bulk. The lower end is then tacked in place by a similarlath l2 and a few long nails such as are indicated at i3 are preferably driven in at intervals in order to aid in supporting the extended bat. It is apparent that the amount of extension of the product may be easily and conveniently regulated so as to fit the installation to spaces of rather widely varying dimensions. Moreover, this novel method of insulating the wall space of a building permits practice was very wasteful of the insulatingmaterial because a relatively thin layer of insulation accomplishes almost as efiective insulatio as a much thicker layer.

If it is desired to market and sell the product in small lots, the unit compression method previously described would probably be used. However, formost commercial applications it is desirable to sell the product in bales consisting of a plurality of the separate compressed pads or bats 1- illustrated in Figure 3. We have found or similar material.

that bales of this type may be conveniently made in a single baling or compressing operation. A suitable apparatus for accomplishing this is illustrated rather diagrammatically in ,Figure 6;

this apparatus, as will be seen by reference tothat figure, includes suitable wall members I5, l6, and I! for defining a rectangularly shaped chamber I8 wherein the compressing is accomplished, and a ram or plunger [9 of suitable dimensions which is movable within this chamber to accomplish the longitudinal compression of the product.

The mode of accomplishing the simultaneous compression of a plurality of pads or bats is substantially as follows: A plurality 'of the ordinary uncompressed bats of the type described in the above mentioned Biederman and Fourness patents, as indicated at'5 in Figure 1, are arranged in a pile, the creping in substantially all of the individual constituent sheets of the bats extending in the same direction, i. e. transversely to the length thereof. The several bats are preferably but not necessarily separated from each other by means of spacing sheets 20 which may conveniently comprise appropriately colored creped or plain tissue paper or thin waxed paper, The sides of the box are rigid and serve to maintain the height of the pile of bats substantially uniform during the compression operation. The width of the bats will ordinarily change but little during the' compression operation; and the use of a closure for the sides of the compression chamber is optional.

The ram I9 is moved from the position shown in dotted lines in Figure 6 to the position shown in full lines in that figure, and the compressing of the entire pile of bats is thereby'simultaneously accomplished. The degree of compression will, of course, vary in accordance with the requirements of the situation. When the ram 19 is in the fully compressed position, the several compressed bats which are now similar to the bat l of Figure 3, may be fastened together into abale, such as is illustrated in Figure 5, by suitable straps or ties which are passed through suitable openings 2! in the ram and in the end of r the baling apparatus. If desired, wooden headers 23 such as are illustrated in Figures 5 and 6 may be introduced into the baling apparatus prior to the compressing operation and cardboards 24 or the like may be placed on the top and bottom of the bale to aidin protecting the same. The ties for fastening the bale together may include straps 25 and wires 26.

It is sometimes desirable that some means he provided whereby all of the compressed bats 1 making up one of these bales may be simultane ously extended through a relatively simple operation. The apparatus and methods of the present invention lend themselves most effectively ,to the accomplishment of this. Particularly, during the baling operation a' suitable adhesive, such as sodium silicate, is placed upon the inner surface of each of the wooden headers 23 immediately prior to the initiation of the compression and baling operation. This adhesive serves to securely aflix the ends of each of the compressed bats. 'I to the headers, 'and when the straps and wires 25 and 26 or other ties are released from the bale, it will be found that the headers 23 remain securely attached to the ends of the bats I, as is shown in Figure 9. Upon the release of the baling straps the bats will generally expand to a slight extent.

With this arrangement. to stretch all of the bats to the desired length, it is necessary merely to fasten one of the headers and to then pull the other header away from the stationary header a suflicient distance to accomplish the desired increase in length of the compressed bats. During the extension of the bats some fiufllng, which may be accomplished by shaking one or both of the headers, will be found to be very desirable. When the bats have been extended to the desired length the headers may be cut oil by any convenient means. The arrangement and method lends itself to quantity production manufacturing methods and in actual practice has been found to operate most satisfactorily.

From the foregoing it will be seen that we have provided a novel type of multi-ply, cellulosic product, and method of manufacturing the same either as individual units or in multiple units such as bales. The product of our invention is capable of being stretched or otherwise extended a very considerable amount to adapt it for use as an insulating material, packing material, liquid absorbing material, or the like. When in the compressed state, this product has numerous advantages over any of the products heretofore known to the art in that it is a relatively dense article which may be shipped at reasonably low cost and which is easy to pack and to handle either as individual pads or in bales. Our invention fully overcomes the serious objections resulting from the extreme bulk and low density of the prior art products.

Probably the most important feature of the novel method of our invention resides in the discovery of the fact that low density, porous batsof the subject type may-be converted, by com-- pression applied longitudinally thereto, in a direction perpendicular to the creping in the individual sheets making up the bats, into a relatively dense product of low bulk which possesses, at least potentially, all of the desirable qualities ofsuch bats prior to the compression. thereof. In fact, the compression and restoration particularly is carried out several times and actually increases the bulk and decreases the-unit density of the restored product as compared with the bulk and unit density of the original pad or bat. In this connection, it should be mentioned that a reduction in length of the original batofflless than one-half is usually not advantageous, and areduction in length to one-twentieth of the original length is usually as much as can be.

- facturing procedures.

,- We have also disclosed certain novel methods whereby compressed material may be prepared for use and installed in the structure with which it is to be used. The inherent ability of thematerial to accommodate itself to varying amounts of extension without impairment of the insulating or other desirable characteristics makes the product particularlysuitable for being used according to these disclosed methods.

It will be apparent to those skilled in the art that various modifications of the above described article'and methods of manufacturing and using the same may be employed. It is our desire. therefore, that the accompanying claim shall be accorded the broadest reasonable construction consistent with the state of the art.

We claim the followingas our invention:

1. A multi-ply, relatively dense, expansible pad or bat, comprising a plurality of sheets of thin,

creped, cellulosic tissue which are arranged in superposed relation with the creping in substantially all of said sheets extending in the same.

direction, each of said sheets having. a dryer basis weight within the range of about 4 to 9 pounds k for 480 sheets 24' x 36 inches, said pad or bat being in an endwise compressed state and being' expansible in an endwise direction to provide a pad or bat of lower stable unit density which is suitable for use as an insulating material, packing material, or the like, said lower, stable unit density being within the range of about 1.25 to 8 pounds per cubic foot. e

.2. A multi-ply, relatively dense,.extensible pad or bat, comprising a plurality of sheets of thin, creped, cellulosic tissue arranged in superposed relation with the creping in substantially all of said sheets extending transversely to the length of said pad. said sheets havinga. dryer basis weight within the range of about 4 to 9 pounds for 480 sheets 24 x 36 inches and having a crepe ratio induced --by endwise compression of'said pad or bat within the range of about 4 to 60, said pad or bat being longitudinally extensible to provide an elongated pad or bat of lower, stable unit density which is suitable for use as an insulating material, packing material, or the like, said lower, stable unit density being within the range of about 1.25 to 8 pounds per cubic foot.

3. A multi-ply, relatively dense, expansible pad or bat, comprising 'a plurality oi sheets of thin, creped, cellulosic tissue which are arranged in superposed relation with the creping in substan-- within the range of about 4 to 9 pounds for480 sheets 24 x 36 inches and a crepe ratio induced by endwise compression of said pad or bat within the range-of about 4 to 60, said pad or bat having a unit-density within the range of about 2.5 to '75 pounds per cubic foot, and being expansible to provide a pad or bat of a-lower, stable unit density which is suitable for use as an insulating material, packing material, said lower unit density being within the range of about 1.25 to 8 pounds per cubic foot.

4. A multi-ply, relatively dense, expansible pad I or bat, comprising a plurality of sheets of thin,

creped, cellulosic tissue which are arranged in superp sed relation with the creping in substantially all of said sheets extending in the same 1 direction, each of said sheets containing at least about 84 to 96% by weight of cellulose fiber, exclusive of clay or like inert filler material, and having a dryer basis weight within the range of about 4 to 9 pounds for 480 sheets 24 x 36 inches, said pad or bat having a unit density induced in part by endwise compression of said pad or bat within the range of about 6 to '25 pounds per cubic foot and being expansible to provide a pad or bat of a lower, stable unit density which is suitable for use as an insulating material, packing material, or the like, said lower, stable unit density being within the range of about 3 to 8 pounds per cubic foot.

5. A multi-ply, relatively dense, expansible pad 7 tially all of said sheets extending in the same direction, each of said sheets containing about 94 to 96% by weight of cellulose fiber, exclusive of clay or like inert filler material, said sheets having a dryer basis weight within the range of about 4 to 9 pounds for 480 sheets 24 x36 inches-and a crepe ratio induced in part by endwise compression of said pad or bat within the range of about 4 to 60, said pad or bat having a unit' density within the range about 6 to 75 pounds per cubic foot and being expansible to provide a pad or bat of a lower, stable unit" density which is suitable for use as an insulating material, packing material, or the like, said lower, stable unit density being within the range about 3 to 8 pounds per cubic foot.

6. A multi-ply, relatively dense, expansible pad or bat, comprising a plurality of sheets of thin, creped, cellulosic tissue which are arranged in superposed relation with the creping in substantially all of said sheets extending in the same direction, said sheets having a dryer basis weight within the range of about 4 to 9 pounds for 480 sheets 24 x 36 inches and containing from to 50% by weight of an asphalt which is relatively brittle at room temperatures and which has a melting point within the range of about 140 F. to 200 F., said asphalt being in the form of small discrete particles of widely varying-dimensions and substantially all of said particles being individually attached to individual fibers or groups of the fibers making up each of said sheets, said pad or bat having a. unit density induced in part by endwise compression of said pad or bat within the range of about 2.5 to 40 pounds per cubic foot and being expansible to provide a pad or bat, of a lower, stable unit density which is suitable for use as an insulating material, packing material, or the like, said lower, stable unit density being within the range of from about 1.25 to 2 pounds per cubic foot.

7. A multi-ply, relatively dense, expansible pad or bat, comprising a plurality of sheets of thin, creped, cellulosic tissue which are arranged in superposed relation with the creping in substantially all of said sheets extending in the same direction, said sheets having a dryer basis weight Within the range of about 4 to 9 pounds for 480 sheets 24 x 36 inches and having a crepe ratio induced at least in part-by endwise compression of said pad or bat within the range of about 4 to 60, each of said sheets containing from 10 to by weight of an asphalt which is relatively brittle at room temperatures and which has a melting point within the range of about F. to 200 F., said asphalt being in the form of small discrete particles of Widely varying dimensions and substantially all of said particles being individually attached to individual fibers or groups of the fibers making up each of said sheets, said pad or bat having a unit density induced in part by endwise compression of said pad or bat within the range of about 2.5 to 40 pounds per cubic foot and being expansible to provide a pad or bat of a lower, stable unit density which is suitable for use as an insulating material, packing material, or the like, said lower, stable unit density being within the range of about 1.25 to 2 pounds per cubic foot.

CHARLES A. FOURNESS. JOHN B. CATLIN. 

